Microelectromechanical systems (MEMS) are the technology of forming micro-structures with dimensions in the micrometer scale (one millionth of a meter). Significant parts of the technology have been adopted from integrated circuit (IC) technology. Most of the devices are built on silicon wafers and realized in thin films of materials. There are three basic building blocks in MEMS technology, which are the ability to deposit thin films of material on a substrate, to apply a patterned mask on top of the films by photolithographic imaging, and to etch the films selectively to the mask. A MEMS process is usually a structured sequence of these operations to form actual devices.
MEMS applications include inertial sensors applications, such as motion sensors, accelerometers, and gyroscopes. Other MEMS applications include optical applications such as movable mirrors, and RF applications such as RF switches and resonators.